In quest of oil, China is on a collision course with U.S. firms and U.S. policy

When Chevron, one of the world's oil giants, announced in early April that it was buying Unocal, a smaller rival, for about $17 billion, it seemed like business as usual in the oil patch: the big getting bigger by swallowing the not quite so big. Across the Pacific, though, management at Chinese National Offshore Oil Corp. (CNOOC), one of China's largest oil firms, was still pursuing what it calls "Operation Treasure Ship." Unocal, some at CNOOC think, fits perfectly into China's fervent effort to secure new oil and gas supplies to fuel its surging economy. Within the next month, CNOOC may...